Federal Labor frontbencher Ed Husic has described some of the anti-Islamic criticism directed towards him as "extreme" but says people have the right to raise concerns about him taking the oath of office on the Koran.

Mr Husic became Australia's first Muslim frontbencher when he was appointed the new Parliamentary Secretary to the Prime Minister and Broadband on Monday.

He has been subjected to religious attacks online for taking his oath of office on the Koran at the swearing in ceremony with Governor-General Quentin Bryce.

On the western Sydney MP's Facebook page, some users said it was "disgusting" and "un-Australian" for him to use the Koran, while one user said it is the same book used by terrorists.

But others leapt to his defence, offering congratulations on his appointment and saying he should "ignore the haters" and "racist rants".

Mr Husic has explained why he used the Koran for his oath, saying it was a straightforward decision.

"I couldn't obviously take my oath on a Bible ... I am who I am," he said.

Mr Husic says he has been heartened by a number of congratulatory messages, adding he knows there are some people who have expressed concerns and asked questions about him using the Koran.

"I also see that as a natural part of democracy and a good thing that people can ask those questions," Mr Husic said.

He says it is "right" for people to express their concerns.

"But I also think that you'll have, from time to time, people at the extremes - there are people definitely that are extreme within my faith and there are people that are extreme outside it - and they will always seek ways in which to divide people," he said.

Mr Husic says the important thing is that mainstream Australia wants everyone to work together and "it's also important that we not necessarily jump because of harsh words out of dark corners."

MPs defend Husic, slam 'appalling behaviour'

There has been an outpouring of support for Mr Husic on social media from politicians of all sides of politics.

"There is definitely elements of extremism and racism in the community, but we need to call it out when we see it no matter what side of the political fence we come from," Mr Frydenberg told ABC 774 Melbourne this morning.

Mr Frydenberg says he is working behind the scenes with Mr Husic to try to bridge divides in the community.

"I know Ed didn't want to come on the show because he doesn't want to beat this story up, but he goes about the work behind the scenes and is a really positive role model for many people in the Islamic community," he said.